Magnetic recording-play-back heads



June 19, 1956 J, E, DE TURK ET AL 2,751,440

MAGNETIC RECORDING-PLAY-BACK HEADS Filed July 22, 1950 2 Sheets-Sheet' 1 nr EY June 19, 1956 J. E. DE TURK ET A1. 2,751,440

MAGNETIC REcoRnmG-PLAY-BACK HEADS 2 Sheets-Sheet 2 Filed July 22 1950 Y /,9 2a .Jllll l' l l FVG. 4-

/A/l/E A/ 7' 0195 JOHN E. aTl/EK J/M/ hf Mac-NEILL United States Patent O MAGNETC 4RECORDING-PLAY-BACK VHEADS Jo'hnE. ADe'lurk, Cambridge, John H. MacNell, Stoughton, and Norman TEliot Gibbs, Waltham, Mass., assignors to Raytheon.Manufacturing Company, Newton, fMass., a corporationof Delaware Application July 22, 1950, SerialNo. 175,402

2 Claims. (Cl. 179-1001) This `invention relates to magnetic .recording and playback heads, and more particularly .to devices of the general character indicated especially adapted for simultaneous .multiple-channel operation.

Existing .devices of this type possess certain-disadvantages. For example, they are bulky; Athey require eX- treme accuracy in their fabrication .and assembly; -they arediicult to replace without risk of loss of synchronism of theinformation recorded on the various channels; and .they are disturbed by an undue amount of cross-talk between said channels.

It is, therefore, the main object .of .the present `invention to eliminate the foregoing disadvantages by providing a head which consists of a plurality-of thin, stacked, single-channel umts which are complete in themselves, which -carry .their own terminals, Aand which maintain proper inter-relationship for their entire useful lives.

:It is another object of the present invention to provide a multiple 'head in which each single-channel unit is a duplicate of each other unit, whereby the single units are interchangeable within a particular multiple head, and the multiple heads are likewise interchangeable in the apparatus in which they are employed.

It is still another object of the present invention to provide a multiple head which requires greatly diminished accuracy in the mounts adapted to receive the same in the apparatus in which they are employed.

It is still another object of the present invention to provide a multiple head which is extremely compact and still incorporates effective shielding for reducing interchannel interference to acceptable limits.

These and other objects of the present invention, which will become more apparent as the detailed description thereof progresses, are attained, broadly, in the following manner.

A magnetizable core provided with pole pieces spaced by a non-magnetic insert to define a working gap has a coil wound thereon. The coil has its ends electrically connected, respectively, to Contact members. Bonded to the side surfaces of the core and contact members are duplicate plastic plates, said plates being provided with recesses receptive of the windings on the core and bosses engaging contact members. The units thus far described are stacked with magnetic shields therebetween and the assembly is held together and maintained in fixed interrelau'onship by locating rods passing through apertures in the shields, side plates and cores.

Magnetic heads embodying the features of the present invention have been constructed and found to have the advantages previously referred to, said advantages having been long sought, for example, in digital computing equipment and data filing systems. The chief virtue of the heads of the present invention is their extreme thinness, heads of .070 inch having been constructed whih permit eticient employment of the medium on which the recording is accomplished.

In the accompanying specification there shall be described, and in the annexed drawings shown, an illusl 2,751,440 Patented June 19, 1956 trative embodiment of the lmagnetic recording-play-back head of the present invention. vIt is, however, to be clearly Aunderstood-that the present invention is not to be limited to 'the Vexact details herein shown and described for purposes of illustration only, inasmuch as changes therein may be `made without the exercise of invention and within the true Aspirit and scope of the claims Vhereto appended.

In -said drawing:

Fig. 4l is an'exploded side elevational view showing the components making up each single-channel unit;

Fig. 2 is aside elevational view of a partially assembled single-channel unit;

Fig. 3 is a similar view of the same completely assembled; and

Fig. 4 is an edge view of an assembled multiple head incorporating a plurality of the single-channel units shown in Fig. 3.

Referring now more in detail to the aforesaid illustrative embodiment of the present invention, with particular referencetto Figs. l, V2 and 3 of the drawings, the numeral 10 generally designates a dat magnetizable core consisting-of amain rectangular portion 1l, a transverse, substantially'rectangular portion 12 at one end of said main portion, and a transverse, substantially triangular portion 13 at the other end of said main portion. As will hereinafter be more fully-described, two such cores are employed, the rectangular portions 12 having abutting inner surfaces 14 to complete the magnetic circuit, and the `triangular portions 1.3, constituting pole pieces, having flattened portions -ISYadapted to support an insert 16 of nomnagnetic material therebetween to dene a working'gap.

v'Each 'of the-'cores 10 has a coil 17 wound on the'main portion 11 thereof, the coils being series-connected by splicing together the lower ends thereof, as at 1S, the upper, free ends thereof being connected, respectively, to contact members 19 and 20. The members 1g and 20 are substantially rectangular in shape, except that their side edges are curved inwardly, as at 21 and 22, lugs 23 depending from the lower edges thereof, and olf-set tongues 24 extending from the upper edges thereof.

A pair of substantially rectangular plastic side plates 25, having rectangular openings 26 separated by elongated bosses 27, is bonded to the side surfaces of the cores 10, the openings 26 being receptive of the coils 17 wound upon said cores. The plates 25 are also bonded to the side surfaces of the contact members 19 and 29, and, through the bosses 27 and 28, to each other, the curved edges 21 and 22 of said contact members engaging substantially elliptical bosses 28 formed on said plates, whereby said contact members are maintained in appropriate alignment.

Fig. 2 of the drawing most clearly shows the cores and contact members in position on one of the side plates, and it is to be noted that said cores and contact members lie in a common plane. The single-channel unit completed by the addition of a second side plate, the completed unit being most clearly shown in Fig. 3 of the drawings.

As best seen in Fig. 4 of the drawings, a plurality of the units shown in Fig. 3 are stacked together with magnetic shields 29 between each pair, the assembly being held together and maintained in proper inter-relationship by locating rods 30 passing through openings 31 in the side plates 25, openings 32 in the cores 10, and, of course, aligned openings (no reference characters) in the shields 29. The openings 32 are accurately located with respect to the surfaces 14 and 15, the openings 31 are slightly larger than the openings 32, and the rods 30 t the openings 32 precisely, so that, when the units are stacked as aforesaid, all of the abutting surfaces 14 and the working "ice gaps become accurately aligned with respect to each other and with respect to the rods 30. The assembly is completed by suitable end plates 33 and 34.

If desired, the rods 30 may be extended beyond the end plate 33 or 34 and the extended portions utilized to eiect precision location of the entire assembly in the apparatus with which it is intended to be used.

This completes the description of the aforesaid illustrative embodiment of the magnetic recording and playback heads of the present invention.

It will be noted from all of the foregoing that the multiple head is extremely compact because of the extreme thinness of Yeach single-channel unit; the singlechannel units are so stacked and maintained in their assembly as to prevent misalignment; the individual units, being identical, are interchangeableyand the multiple heads themselves are of such construction as to enable interchangeability with like heads in the apparatus in which theyare intended to be used.

Other objects and advantages of the device of the present invention will readily occur to those skilled in the art to which the same relates.

What is claimed is:V

1. A multiple magnetic recording and play-back head comprising: an assembly of superposed units, each including :a magnetizable core providing pole pieces spaced to dene a working gap, a coil Wound upon said core, contact members electrically connected, respectively, to the ends of said coil, and support plates, having substantially greater mass than said core, bonded, respectively, to opposite sides of said core and said contact members, said plates incorporating recesses receptive of said coil, and bosses engaging said contact members; a

magnetic shield, substantially coextensive with said plates, disposed intermediate each pair of said units; and a plurality of guide rods passing through apertures in said cores, plates and shields to maintain said units in fixed 4V inter-relationship, with said Working gaps in alignment with each other. t

2. A multiple magneticrecording and play-back head comprising: an assembly of superposed units, each including a magnetizable core providing pole pieces spaced to dene a Working gap, a coil Wound upon said core, contact members electrically connected, respectively, to the ends of said coil, `and support plates bonded, respectively, to opposite sides of said core and said'contact members; and ia plurality of guide rods passing through apertures in said cores and Said plates to maintainsaid assembly of units in xed inter-relationship; the apertures in said cores being smaller than the apertures in said plates and providing a precise lit with said guide rods.

References Cited in the file of this patent UNITED STATES PATENTS 2,195,192 Y Schuller Mar. 26, 1940 2,456,767 Camras Dec. 21, 1948 2,493,742 Begun Ian. 10, 1950 2,513,617 Begun July 4, 1950 2,513,653 Kornei f July 4,/1950 2,517,808 Sziklai Aug. 8, 1950 2,523,576 Kornei Sept. 26, 1950 2,535,480 Begun Dec. 26, 1950 2,536,272 Friend Jan. 2, 1951 2,538,405 Zenner Jan. 16, 1951 2,540,654 Cohen Feb. 6, 1951 2,549,771 Camras Apr. 24, 1951 2,551,935 Flood May 8, 1951 2,563,445 Zenner Aug. 7, 1951 2,574,707 Pettus Nov. 13, 1951 2,574,898 Behren Nov. 13, 1951 2,590,292 Anderson Mar. 25, 1952 2,618,709 Eckert Nov. 18, 1952, 

